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Acetyl-L-carnitine (ALCAR)

Acetylated carnitine with Cochrane signal for diabetic neuropathy and small-RCT signal for chronic fatigue and mild cognitive complaints.

Why

Acetyl-L-carnitine (ALCAR) is the acetylated form of L-carnitine, better blood-brain-barrier penetration than carnitine itself. The Cochrane review of ALCAR for painful peripheral neuropathy (Li 2015) found significant pain reduction in diabetic and chemotherapy-induced neuropathy. Smaller bodies of work in chronic fatigue (the Vermeulen RCT) and mild cognitive impairment show modest signal. Effect on healthy young adults is small.

How it works

Provides the acetyl group for acetylcholine synthesis, supports mitochondrial fatty-acid transport (the classical carnitine role), and crosses the blood-brain barrier where it modulates monoaminergic transmission and NGF activity in animal models.

Expected onset · Neuropathy effects over 8–12 weeks; cognition/fatigue effects over 4–8 weeks

How to take

Dosage

Neuropathy: 1,000 mg twice daily. Cognition/fatigue: 1,500–3,000 mg/day divided.

Timing

Divided 2–3 times daily, away from large protein meals

On the label

'Acetyl-L-carnitine HCl' (or ALCAR) with stated mg per dose. Distinguished from plain L-carnitine and from L-carnitine tartrate (used more for athletic recovery).

Ideal for

Adults with painful diabetic or chemotherapy-induced peripheral neuropathy under clinical guidance; older adults with subjective cognitive complaints; people with chronic fatigue exploring nutrient adjuncts.

Safety

Generally well tolerated. Possible activation, restlessness, insomnia at higher doses. Avoid late dosing. Theoretical risk of seizure-threshold lowering in epilepsy. Caution with thyroid hormones (may reduce thyroid hormone action). Pregnancy: limited data; coordinate with the prescribing clinician.

Evidence

At a glance

Cochrane 2015 SR on ALCAR for diabetic neuropathy: significant reduction in pain at 1,000 mg twice daily vs placebo. Cochrane 2003 SR for dementia found short-term improvement in mild cognitive impairment but no clear effect on established dementia. Strongest signal is in painful peripheral neuropathy.

Where to get it

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